1. Field of the Invention
The present invention relates to communication systems. More specifically, the present invention relates to switching systems used satellite communication applications.
2. Description of the Related Art
Intermediate frequency (IF) crosspoint switches are used on satellites to provide routing and redundancy between data communication channels. The channels route IF signals and data in a link between antennas via the downconversion circuitry of an IF receiver and the upconversion circuitry of a radio frequency (RF) transmitter within the communications payload of the satellite.
Previously, crosspoint switches were implemented on multiple chips, typically in a 50 ohm environment and with Gallium Arsenide (GaAs) technology. The GaAs approach required GaAs switches, low noise amplifiers (LNAs) and attenuators. This also typically required the use of complementary metal-oxide semiconductor (CMOS) integrated circuits to provide selectable control of the numerous connections needed to provide redundancy and routing between the chips.
Accordingly, conventional crosspoint switches were large, heavy, expensive devices that dissipated a considerable amount of power due to the need for multiple individually packaged components that required a characteristic impedance match interface.
In addition, as a result of using individual GaAs chips to implement an IF switch function, a large amount of routing lines were required on the board which tended to degrade channel-to-channel isolation. There were also unacceptable gain variations as a function of the output channels selected.
Hence, a need exists in the art for a low power dissipation, small, lightweight inexpensive system or method for effecting switching and routing data between channels within a satellite communications payload which provides acceptable channel-to-channel isolation and gain uniformity.